APA (7th ed.) Citation

Blackstock, C. (1966). The knock at midnight. Hodder & Stoughton.

Chicago Style (17th ed.) Citation

Blackstock, Charity. The Knock at Midnight. London: Hodder & Stoughton, 1966.

MLA (8th ed.) Citation

Blackstock, Charity. The Knock at Midnight. Hodder & Stoughton, 1966.